maybe your service book is being used to insulate your doors and got wet hence why you cant find it?
Don't go there, have been totally let down by the dealer and SEAT UK.
As for my car steaming up, its just another thing to add the list of retarded SEAT moments.
My hint/tip for ways around this are:-
1) Put the blowers on full to your feet until the wock with and air comes through then stick them on the windscreen.
2) Do not under any circumstances use the actual window demist button. I don't know what it does but it's defo not window demisting.
3) Get a chamois sponge thing from halfauds / other recommended shops and use that to clear the inside of the screen until you can see where you are going.
4) Stop breathing. Do not breath inside the car what-ever you do. Get a snorkel and breath through that. I think you may be able to run this throught the door seal gaps with-out it making any difference.
Good luck with it.